Cascading failure of Mullaperiyar, Idukki Dams will affect 50 lakh people: Kerala to Supreme Court

The Kerala government has told the Supreme Court that any failure of the 126-year-old Mullaperiyar Dam built across the Periyar River could have a cascading effect on the Idukki Dam situated downstream, and that the combined failure of the two dams will have a catastrophic impact on the lives and properties of 50 lakh people..In an affidavit filed before the top court, the State of Kerala also submitted that in the past few years, erratic rainfall patterns caused due to climate change have led to instances of sudden spikes in the water levels of the Dam's reservoir."If water level at Mullaperiyar is kept at a higher level, releases from it will be affecting the already filled Idukki reservoir. In worst case of a cascading failure of Mullaperiyar and Idukki, will result in a catastrophe which is beyond imagination affecting the life and property of 50 lakhs of people residing below the Idukki dam," the affidavit said..It, therefore, urged the top court to reduce the maximum permissible water level in the reservoir, which is currently fixed at 142 feet."It is submitted that in view of the recent incidents of heavy rainfall in the State of Kerala and specifically in the catchment of the Mullaperiyar dam (particularly in 2018 and 2019) and consequent sudden surge in the reservoir levels, projected change in rainfall patterns due to climatic change and its impact on floods the fixing of Upper Rule level at 142 feet during 20th September as formulated by Tamil Nadu may be reconsidered," the affidavit stated.As a long term measure, the Kerala government submitted that the Dam should be decommissioned and that a new Dam should be built downstream."The State of Kerala submits that the only permanent solution for removing the eternal threat owing to the safety concerns of the 126 year old existing dam in Mullaperiyar and for protecting the safety of the lakhs of people living in the downstream of Mullaperiyar dam, is to build a new dam in the downstream reaches of the existing Mullaperiyar dam." .The affidavit was filed in a plea by the Kerala government to ensure that the water level in the Dam's reservoir is not allowed to exceed 139 feet, three feet below the permissible limit of 142 feet prescribed by the 2014 judgment of the top court.The Supreme Court had in 2018 passed an order to maintain the water level at 139 feet during the Kerala floods as a temporary arrangement.The Kerala government in its present plea has asked for a similar direction in view of the incessant rains in the State which has led to a rise in the water level of the reservoir..When the matter was heard on October 25, the Court had observed that the issue surrounding fixing of maximum water level was a serious one, but was not something which the Court can decide upon, since it lacks the expertise for the same.A Bench of Justices AM Khanwilkar and CT Ravikumar, had therefore, said that it is the task of the expert supervisory committee appointed by the Court to decide the same. It asked the committee to take a call expeditiously after discussing with all parties concerned.Pursuant to that, the expert committee had met and suggested that no change in water level is required.The Kerala government had, however, dissented and filed a note setting out its concerns. Subsequently, it had told the Court that it will file a detailed affidavit in this regard.